/*
* Copyright (C) 2015 SoftIndex LLC.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package io.datakernel.stream;
import io.datakernel.async.AsyncCallable;
import io.datakernel.async.CompletionCallback;
import io.datakernel.async.ResultCallback;
import io.datakernel.eventloop.Eventloop;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.ArrayList;
import java.util.List;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Preconditions.checkState;
public final class StreamConsumers {
private StreamConsumers() {
}
public static <T> Idle<T> idle(Eventloop eventloop) {
return new Idle<>(eventloop);
}
public static <T> ClosingWithError<T> closingWithError(Eventloop eventloop, Exception exception) {
return new ClosingWithError<>(eventloop, exception);
}
/**
* Returns {@link ToList} which saves received items in list
*
* @param eventloop event loop in which will run it
* @param list list with received items
* @param <T> type of item
*/
public static <T> ToList<T> toList(Eventloop eventloop, List<T> list) {
return new ToList<T>(eventloop, list);
}
/**
* Returns {@link ToList} which saves received items in empty list
*
* @param eventloop event loop in which will run it
* @param <T> type of item
*/
public static <T> ToList<T> toList(Eventloop eventloop) {
return toList(eventloop, new ArrayList<T>());
}
public static <T> StreamConsumer<T> asynchronouslyResolving(final Eventloop eventloop, final AsyncCallable<StreamConsumer<T>> consumerGetter) {
final StreamForwarder<T> forwarder = StreamForwarder.create(eventloop);
eventloop.post(new Runnable() {
@Override
public void run() {
consumerGetter.call(new ResultCallback<StreamConsumer<T>>() {
@Override
protected void onResult(StreamConsumer<T> result) {
forwarder.getOutput().streamTo(result);
}
@Override
protected void onException(Exception exception) {
forwarder.getOutput().streamTo(new ClosingWithError<T>(eventloop, exception));
}
});
}
});
return forwarder.getInput();
}
public static final class ClosingWithError<T> extends AbstractStreamConsumer<T> implements StreamDataReceiver<T> {
protected static final Logger logger = LoggerFactory.getLogger(ClosingWithError.class);
private CompletionCallback callback;
private final Exception exception;
public void setCompletionCallback(CompletionCallback callback) {
if (getConsumerStatus().isOpen()) {
this.callback = callback;
} else {
if (getConsumerStatus() == StreamStatus.END_OF_STREAM) {
callback.setComplete();
} else {
callback.setException(getConsumerException());
}
}
}
public ClosingWithError(Eventloop eventloop, Exception exception) {
super(eventloop);
this.exception = exception;
}
@Override
protected void onError(Exception e) {
if (callback != null) {
callback.setException(e);
}
}
@Override
protected void onStarted() {
logger.trace("Closing with error {}", exception.toString());
closeWithError(exception);
}
@Override
public StreamDataReceiver<T> getDataReceiver() {
return this;
}
@Override
public void onData(T item) {
closeWithError(exception);
}
}
/**
* Represents a simple {@link AbstractStreamConsumer} which with changing producer sets its status as complete.
*
* @param <T> type of received data
*/
public static final class Idle<T> extends AbstractStreamConsumer<T> implements StreamDataReceiver<T> {
protected Idle(Eventloop eventloop) {
super(eventloop);
}
@Override
public StreamDataReceiver<T> getDataReceiver() {
return this;
}
@Override
public void onData(T item) {
}
}
/**
* Represents a {@link AbstractStreamConsumer} which adds each item of received data to List.
*
* @param <T> type of received data
*/
public static final class ToList<T> extends AbstractStreamConsumer<T> implements StreamDataReceiver<T> {
protected final List<T> list;
private CompletionCallback completionCallback;
private ResultCallback<List<T>> resultCallback;
/**
* Creates a new instance of ConsumerToList with empty list and event loop from argument, in which
* this customer will run
*/
public ToList(Eventloop eventloop) {
this(eventloop, new ArrayList<T>());
}
public void setCompletionCallback(CompletionCallback completionCallback) {
if (getConsumerStatus().isOpen()) {
this.completionCallback = completionCallback;
} else {
if (getConsumerStatus() == StreamStatus.END_OF_STREAM) {
completionCallback.setComplete();
} else {
completionCallback.setException(getConsumerException());
}
}
}
public void setResultCallback(ResultCallback<List<T>> resultCallback) {
if (getConsumerStatus().isOpen()) {
this.resultCallback = resultCallback;
} else {
if (error != null) {
onError(getConsumerException());
} else {
onEndOfStream();
}
}
}
@Override
protected void onEndOfStream() {
if (completionCallback != null) {
completionCallback.setComplete();
}
if (resultCallback != null) {
resultCallback.setResult(list);
}
}
@Override
protected void onError(Exception e) {
if (completionCallback != null) {
completionCallback.setException(e);
}
if (resultCallback != null) {
resultCallback.setException(e);
}
}
/**
* Creates a new instance of ConsumerToList with
*
* @param eventloop event loop in which this customer will run
* @param list list for adding received items
*/
public ToList(Eventloop eventloop, List<T> list) {
super(eventloop);
checkNotNull(list);
this.list = list;
}
/**
* Returns list with received items
*/
public final List<T> getList() {
checkState(getConsumerStatus() == StreamStatus.END_OF_STREAM, "ToList consumer is not closed");
return list;
}
@Override
public StreamDataReceiver<T> getDataReceiver() {
return this;
}
@Override
public void onData(T item) {
list.add(item);
}
}
public static final class ToListSuspend<T> extends AbstractStreamConsumer<T> implements StreamDataReceiver<T> {
private List<T> list;
private boolean endOfStream;
protected ToListSuspend(Eventloop eventloop) {
this(eventloop, new ArrayList<T>());
}
public ToListSuspend(Eventloop eventloop, List<T> list) {
super(eventloop);
this.list = list;
}
@Override
protected void onEndOfStream() {
endOfStream = true;
}
@Override
protected void onError(Exception e) {
closeWithError(e);
}
@Override
public StreamDataReceiver<T> getDataReceiver() {
return this;
}
@Override
public void onData(T item) {
list.add(item);
suspend();
}
public final List<T> getList() {
return list;
}
public boolean isEndOfStream() {
return endOfStream;
}
public Exception getOnError() {
return error;
}
}
public static <T> ToListSuspend<T> toListSuspend(Eventloop eventloop, List<T> list) {
return new ToListSuspend<T>(eventloop, list);
}
public static <T> ToListSuspend<T> toListSuspend(Eventloop eventloop) {
return toListSuspend(eventloop, new ArrayList<T>());
}
}